1. Field
Example embodiments may relate to a method of reading data of a memory device. In particular, example embodiments may relate to a method and a device for reading data of either a multi-level cell (MLC) memory device or a multi-bit cell (MBC) memory device.
2. Description of Related Art
A single-level cell (SLC) memory device may store one bit of data in a single memory cell. The SLC memory may be referred to as a single-bit cell (SBC) memory.
Storing of one bit of data in an SLC of the SLC memory may be referred to as a programming operation that may change a threshold voltage of the SLC. The SLC may have either a low threshold voltage level or a high threshold voltage level depending on whether the one bit of data stored in the SLC is “0” or “1”. Reading of data stored in the SLC may be implemented by sensing the threshold voltage level of the SLC and determining whether the sensed threshold voltage level is either higher or lower than a reference voltage level.
The threshold voltages of the programmed cells may have a distribution within a certain range due to a fine electric characteristic difference between the SLCs. For example, when a sensed voltage level of an SLC is greater than 0.5V and less than 1.5V, it may be determined that the data stored in the memory cell has a logic value of “1”. When the sensed voltage level of an SLC is greater than 2.5V and less than 3.5V, it may be determined that the data stored in the memory cell has a logic value of “0”.
Sensing of the threshold voltage level of the SLC may be implemented by applying a certain level of voltage to a gate terminal of the SLC, and also by sensing an amount of electric current flowing between a source terminal and a drain terminal of the SLC.
Meanwhile, a multi-level cell (MLC) memory device that can store two or more bits of data in a single memory cell has been proposed in response to a need for higher integration of memory. The MLC memory device may also be referred to as a multi-bit cell (MBC) memory.